Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 251128
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
728 AM EDT TUE AUG 25 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 409 AM EDT TUE AUG 25 2015

00Z RAOBS/LATEST WV IMAGERY AND RAP ANALYSIS SHOW UNSEASONABLY DEEP
CLOSED LO IN ONTARIO JUST NE OF LK SUP DRIFTING SLOWLY TO THE E...
WITH SHARP CYC FLOW ARND THIS FEATURE DOMINATING THE GREAT LKS.
LOCAL RAOBS INDICATE THE SFC-H7 LYR IS QUITE MOIST WITH H925...H85
AND H7 DEWPT DEPRESSIONS AT INL AND E NO MORE THAN A FEW DEGREES C.
THERE ARE ALSO TWO SHRTWVS OF NOTE ROTATING ARND THE LARGER SCALE
FEATURE. THE FIRST OF THESE IS NOW HEADING INTO NRN LK MI AT THE
BEGINNING OF THE SHIFT AND TAKING THE MORE WIDESPREAD SHOWERS THAT
HAD IMPACTED THE ERN CWA LAST EVNG TO THE SE WITH IT. IN THE WAKE OF
THIS DISTURBANCE...SFC OBS AND THE MQT 88D INDICATE RELATIVELY FEW
SHOWERS...MAINLY JUST SOME DRIZZLE...LINGER OVER UPR MI EARLY THIS
MRNG DESPITE THE MOIST LLVLS AND SHARP CYC NW FLOW. THE CULPRITS
APPEAR TO BE LARGER SCALE QVECTOR DVGC TO THE W OF THE CLOSED LO AND
BEHIND THE DEPARTING SHRTWV AND RATHER SHARP H875-85 INVRN SHOWN ON
THE 00Z INL/YPL RAOBS ASSOCIATED WITH THESE NEGATIVE DYNAMICS/HGT
RISES THAT IS LIMITING THE LK EFFECT COMPONENT TO THE NE OF H85
THERMAL TROF CENTERED ON AN AXIS FM INL TO GRB. 00Z H85 TEMPS WERE
3C AT INL AND GRB...BUT 10C AT YPL. WV IMAGERY/RAP ANALYSIS INDICATE
ANOTHER SHRTWV ROTATING SWD TO THE W OF THE CLOSED LO IS DROPPING
THRU NW ONTARIO. THE LATEST THUNDER BAY RADAR SHOWS AN AREA OF MORE
NMRS SHOWERS OVER LK NIPIGON MOVING INTO NRN LK SUP.

MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON POPS ASSOCIATED SHRTWV
ROTATING SWD ARND SLOWLY DEPARTING CLOSED LO.

TODAY...WHILE ONTARIO SHRTWV MOVING TO THE S IS ON TRACK TO MOVE
INTO NRN LK SUP THIS MRNG...MODELS INDICATE DEEP LYR QVECTOR DVGC
AND HGT RISES...FCST TO BE ABOUT 50M BTWN 12Z-24Z TODAY...LEFT IN
THE WAKE OF THE CLOSED LO WL DOMINATE. SO ALTHOUGH FCST PROFILES
INDICATE SOME DEEPENING MSTR THRU THIS MRNG...THEY ALSO SHOW A NEAR
ABSENCE OF ANY UVV...IN FACT MAINLY LARGE SCALE SUBSIDENCE THAT WL
MAINTAIN THE INVRN NEAR H85 AND LIMIT POPS. THE ERN CWA HAS A BETTER
CHC TO SEE THE HIER POPS...AS THIS AREA WL BE CLOSER TO THE
DEPARTING DISTURBANCE/WEAKER SUBSIDENCE WITH AT LEAST SOME UVV/
SHARPER CYC FLOW AND DOWNSTREAM OF LK SUP IN PERSISTENT NW FLOW THAT
WL ACCENTUATE LLVL CNVGC. GIVEN THESE NEGATIVES...TENDED TO LOWER
GOING POPS. PLENTY OF LO CLDS WL LIMIT THE DIURNAL TEMP RECOVERY
AGAIN DESPITE SLOWLY MODERATING H85 TEMPS THAT WL ALLOW FOR A WARMER
DAY THAN YDAY. THE STEADY/GUSTY NW WINDS WL CONTINUE TO WHIP UP HI
WAVES ON LAKE SUP...RESULTING IN A HI SWIM RISK FOR MARQUETTE AND
ALGER COUNTIES.

TNGT...WITH CONTINUED SLOW HGT RISES/DEEP LYR QVECTOR DVGC/WEAKENING
LLVL CYC FLOW TO THE W OF WEAKENING CLOSED LO THAT IS FCST TO LIFT
NE TOWARD THE S END OF JAMES BAY BY 12Z WED...EXPECT DIMINISHING
POPS. THIS TREND WL BE MOST PRONOUNCED OVER THE W...WHERE THE LLVL
FLOW WL BECOME MORE ACYC CLOSER TO APRCHG SFC HI PRES MOVING INTO
MN. LINGERING LO CLDS WL LIMIT THE DIURNAL TEMP FALL. EXPECT THE
COOLEST OVERNGT LOWS TOWARD THE MID 40S OVER THE INTERIOR W...WHERE
THERE COULD BE SOME PARTIAL CLRG LATE WITH THE APRCH OF THE SFC HI
PRES.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 251 AM EDT TUE AUG 25 2015

COULD SEE SOME ISOLATES SHOWERS OVER THE ERN CWA WED MORNING AS NW
WINDS AND 850MB TEMPS OF 5-6C ALLOW FOR LAKE ENHANCED RAIN...BUT
OVERALL FORCING WILL BE WEAK. HIGH PRESSURE MOVING IN WILL BRING AN
END TO RAIN POTENTIAL BY WED AFTERNOON. HIGHS WED IN THE 60S WILL
COMBINE WITH GOOD RADIATIONAL COOLING...DRY CONDITIONS AND LIGHT
WINDS WED NIGHT TO BRING LOWS IN THE 40S INLAND...WITH A FEW SPOTS
IN THE UPPER 30S.

SW FLOW AS THE HIGH MOVES OUT WILL BRING 850MB TEMPS UP TO 14C BY
THE END OF THE DAY THU...RESULTING IN NEAR NORMAL HIGHS IN THE LOW
TO MID 70S. DRY WEATHER PERSISTS THROUGH THU.

MODELS CONTINUE TO INDICATE A COLD FRONT MOVING S FROM CANADA AND
INTO THE CWA THU NIGHT AND FRI WHILE A SHORTWAVE RIDES DOWN NW FLOW
AND PASSES OVER OR NEAR THE CWA. MODELS HAVE BEEN VARIABLE WITH
SOLUTIONS FOR THIS TIME PERIOD...BUT THE ECMWF HAS BEEN THE MOST
STEADY. OVERALL...CHANCES FOR SHOWERS AND THUNDERSTORMS SEEM
REASONABLE.

PRECIP IS QUESTIONABLE FOR SAT...BUT COULD SEE SOME SHOWERS IF
SHORTWAVE ENERGY MOVES THROUGH. LEFT SLIGHT CHANCE POPS FOR NOW.
TEMPS LOOK SIMILAR TO FRI.

TEMPS LOOK TO BE ABOVE NORMAL SUN AND MON WITH DRY WEATHER AS
RIDGING BUILDS OVER THE AREA. HIGHS SHOULD RANGE FROM THE MID/UPPER
70S TO LOW 80S.
&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 726 AM EDT TUE AUG 25 2015

A GUSTY NW FLOW OF COOL...MOIST AIR AROUND LO PRES TO THE NE OF LAKE
SUPERIOR WILL BRING PREVAILING MVFR CONDITIONS TO THE TAF SITES THIS
FCST PERIOD. THE ONE EXCEPTION WL BE AT IWD TNGT...WHEN THE CLOSER
APRCH OF HI PRES AND SOME DRYING/A WEAKENING OF THE LLVL CYC FLOW WL
LIKELY ALLOW AN IMPROVEMENT TO MARGINAL VFR. SOME -SHRA/-DZ
ASSOCIATED WITH A PASSING UPR DISTURBANCE THIS MRNG MAY BRING SOME
BRIEF IFR CONDITIONS TO MAINLY CMX...BUT THIS POTENTIAL WL DIMINISH
BY LATE MRNG FOLLOWING THE PASSAGE OF THAT DISTURBANCE. THE
STRONGEST WIND GUSTS UP TO 25 KTS WL OCCUR AT THE MORE EXPOSED CMX
SITE THRU TODAY...BUT EVEN THERE THE WINDS WL DIMINISH THIS EVNG
WITH LOSS OF HEATING/SLOWLY WEAKENING PRES GRADIENT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 409 AM EDT TUE AUG 25 2015

SHARP PRES GRADIENT ON THE WESTERN FLANK OF DEEP LO PRES MOVING THRU
ONTARIO TO THE E OF LAKE SUPERIOR WILL MAINTAIN NW WINDS UP TO 30
KTS TODAY. THE PASSAGE OF A DISTURBANCE THIS MORNING MAY CAUSE SOME
GALE FORCE GUSTS IN A CORRIDOR OVER THE CENTRAL LAKE. BUT AS THE LO
TO THE E WEAKENS AND MOVES TOWARD JAMES BAY TONIGHT...APPROACHING HI
PRES/WEAKENING PRES GRADIENT WILL CAUSE WINDS TO DIMINISH W-E. AS
THE HI MOVES OVER THE UPPER LAKES LATE WED/WED NIGHT...EXPECT WINDS
TO FALL UNDER 20 KTS. A RELATIVELY FLAT PRES GRADIENT WILL DOMINATE
LATE WEEK INTO THE WEEKEND...SO WINDS FOR THE MOST PART SHOULD BE
UNDER 20 KTS.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...BEACH HAZARDS STATEMENT INTO THIS EVENING FOR
                 MIZ005-006.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...KC
LONG TERM...TITUS
AVIATION...KC
MARINE...KC



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